Process of making anthraquinone-disulphonic acid



Patented July 16, 1929. r I I UNITED STATES PATENT oFHc-E. j

DONALD ROGERS-A1\\H IAROLD r. srowEL'L, or BUFFALO, NEW Yoax, ASSIGNORS 'To NATIONAL A ILENEecHEMIcAL COMPANY, me, or NEW YORK, N. Y., A coa- PORA'IION on NEW YoRK.

PROCESS OF MAKING ANTHRAQUINONE-DISULPHONIC ACID.

Ito Drawing. I Application filed November, 21, 1923. Serial No. 676,162.

This invention'relates to improvements in greater part of anthraquinone 1.5 and 1.8 the manufacture and production of anthmdisulphonic acids, there being present, if quinone-alpha-disulphonic acids. 7 any, only relatively small proportions of the It has been heretofore proposed to prepare isomeric alpha-beta: and beta-beta-disulanthraquinone-alpha-alpha-disulphonic acids phonic acids, anthraquinone-monosulphonic by the sulphonation of anthraquinone in the acid, and phenolic bodies orphenolic sulpresence of mercury or its compounds with phonic acids. I v oleum containing a comparatively high per- According to the persent invention, we use centage of free sulfuric anhydride, e. g., about oleum containing a relatiely low percentage 710 40 to 44% free sulfuric anhydride; but while of free sulfuric anhydride' and in suflicient this method results in substantially complete quantity so that the total amount of free sulsulphonation of the anthraquinone, there is furic anhydride is equal to or somewhat formed a complex mixture containing, inadgreater than the amount required for the didition to the alpha-alpha-disulphonic acids, sulphonation of the anthraquinone. 15 lesser proportions of the alpha-monosulphonic While the oleum can be added progressiveacid and of the alpha-beta and beta-beta-di- 1y or in successive amounts, we find it of adsulphonic acids, and greater or lesser amounts vantage to add all or practically all of the of undesirable phenolic bodies or phenolic oleum at the outset, although small additional sulphonic acids from whichit is troublesome. amounts may be added near the end of the 20 to separate the alpha-alpha-disulphonic acids process to complete the sulphonation. in a pure state. p I In carrying out the invention, the anthra It has also been proposed to sulphonate an quinone is advantageously admixed initially thraquinone in the presence of mercury or its with the oleum containing about 15 to 30 percompounds with oleum containing a relativecent, preferably about 24 c26 percent, of free ly low percentage content of free sulfuric ansulfuric anhydride, andin the presence of hydride, e. g., about 20 to 29% free'sulfuric mercury or its compounds,and the admixture anhydride, but such sulphonation has p-rois heated to a temperature of about 140160 duced chiefly the anthraquinone-alpha-mon- 0., preferably to about 150155 0., until subosulphonic acid together with small and varystantially no unchanged anthraquinone is ing amounts of anthraquinone-alpha-alphapresent as shown by a test portion of the mix- 80 dlsulphonic acids, whileaconsiderable part of llrc being completely soluble, .or nearly so, the'anthra quinone has remained unsul hoin water. The amount of oleum employed is nated. ,Ithas also been proposed to subject equal t0 som a o preferably an exthe anthraquinone-monosulphonic acid in the 068% Of about 5 t0 1 p rcent, th n ha lleO- 35 presence of mercury or its compounds to su1-' ljetically required to effect the disulphonaphonation with oleu containing a, co mtlon of the anthraquinone by the action of the 'tively. high percentage content of free sulfuric fr S lfuric anhydride present. a

anhydride, e. g., about 40% free sulfuric an h a p a-alpha-di p onic ids n be hydride, to produce 'the alpha-alpha-disulisolated from the sulphonation mass .in any phonic acids therefrom. t suitable and well known manner, as for ex- 0 We have now found that anthraquinonecan. ample, by diluting the mass with water and be substantially completely 'sulphonated to adding'p'o'tassiumior sodium chloride to the the disulphonic acid by treating it," in solution, whereby the 1.5 and 1.8 disulphonic the presence of mercury or its compounds, acid separate out as their potassium or 5 with a sufiicient amount of oleum, (that is, sodium salts, particularly upon cooling the i fuming sulphuric acid),containingarelative mixture and after standing for sometime,

ly low percentage of free sulfuric anhydride, andcan be'filtered off. They are substantialfor example, oleum containing'about 15 to 30% lyfree from anthraquinone monosulphonic of .free sulphuric anhydride, and that the re- 'acid, alpha-beta -and .-beta-beta disulphonic 50 sulting sulphonation mixture consists for the acids, and from phenolic bodies and their sul- 10o phonic acids.. The quality of the anthraquinone-alpha-alpha-disulphonic acids thus pro- 6 duced is excellent and the yields are superior to those obtained by heretofore proposed 5 methods, so far as we are aware.

The following specific example will further illustrate the invention, but it is understood that the invention'is not limited thereto. Th parts are by weight.

- Example: 100 parts anthraquinone are added to about 325 parts of 26 percent oleum containing 2parts mercurous sulfate. The mixture is heated quickly to a temperature of about 150-155 and kept at this temperature until there is no unchanged anthraquinone present as shown by a test portion being completely soluble, or nearly so, in water. Substantially complete solution, or nearly so, is usually obtained upon sulphonation at this temperature for about -35 minutes. If the product is not completely soluble, or nearly so, in water at the end of this time, a small amount of additional 26 percent oleum is added, and the heating is continued 25' for a few minutes longer or until a test portion shows substantially complete solution of the product. When the sulphonation is complete, the melt is -added to about 2000-2100 parts water, about 500-550 parts common salt 30 are then added, and the mixture cooled to about 15 G2, with stirring. After standing for about 12-15 hours the precipitated mixture of sodium salts is filtered off and washed with salt solution. The product as thus obtained consists chiefly of a mixture of the sodium salts of anthraquinone 1.5 and 1.8 disul honic acids and is substantially free from ant raquinone monosulphonic acid, and from alpha-beta and beta-beta disulphonic acids,

and from phenolic bodies or their sulphonic acids. The quality of the product is excellent and the yield is superior to that obtained by heretofore. proposed processes- If desired, the 1.5 and 1.8 disulpho-acids or their sodium salts can be separated from each other weaker than 26 percent, for example, a 20 in any suitable and well'known manner.

If, in the above example, the sulphonation is carried out at'the same temperature but with an equivalent amount of an oleum percent oleum, the time required to complete the sulphonation will usually be somewhat longer.

It is to be noted that the resent ipvention makes it possible to comp etely su phonate anthraquinone in the presence of mercury or its compounds and obtain anthroquinone-al; pha-alpha-disul'phonic ,acids in superior yields and in an excellent state of purity by the use of oleum containing 15.130 30 percent w free sulfuric anhydride as the sulphonating agent. An oleum of this stren h' is much more readily handled, it being a iquid at ordinary temperatures, than an oleum of 40 to term mercury includes mercur 4.4 percent strength, the latter being a solidat ordinary temperatures. Moreover, the

weaker oleum is less costly'and this gives aneconomic advantage to the invention. Further, the invention produces less by-products and somewhat larger yields than prior processes.

In theclaims it will be understood that the and its compounds, such as mercurous and mercuric salts, mercurous or mercuric oxide, etc.

We claim:

1. The improvement in the sulphonation of anthraquinone to form anthraquinone 1 .5 and 1.8 disulphonic acids which comprises subj ecting anthraquinone, in the presence of mercury, to sulphonation at a temperature of about 140-160 G. with oleum containing about 24-26 percent free sulpfuric anhydride, the amount of oleum employed being sufficient to disulphonate all of the anthraquinone with the free sulfuric anhydride present, and heating the mixture until the sul-1 phonation mass is substantially completely soluble in water.

2. In the production of anthraquinonealpha-alpha disulphonic acids by heating an admixture of anthraquinone, mercury and oleum containing about 15 to 30 per cent freesulfuric anhydride, the steps whichc'omprise employing an amount of said oleum at least suflicient to furnish enough sulfuric anhydrideto completely sulphonate the anthraquinone to the disulphonic acid, heating the admixture to a temperature of about temperature of about 150-155 C.

4. The process of manufacturing anthraquinone 1.5 and 1.8 disulphonic acids which comprises treating anthraquinone, inthe presence of mercury, with an amount of oleum containing at least suflicient free sulfuric anhydride to form anthraquinone disulphonic acid, the initial strength of the oleum being such that it contains about 24-26 percent free sulfuric anhydride, and at a temperature of about 150-155 C. until the sul honation mixture is. substantially complete y soluble in water, and subsequently adding the mixture to water, salting out the anthraquinone 1.5 and 1.8 disul honic acids as their sodium salts from the so ution by adding common salt thereto and removing the precipitated sodium tainingit at this temperature until the sulsalts by filtration. phonation mixture is substantially complete- 5. The method of sulphonating anthra- 1y soluble in water.

quinone which comprisesadding 100 parts In testimony whereofwe afiix our signa- 5 anthraquinone to about 325 parts of 24-26 tures.

percent oleum containing about two parts I mercurous sulfate, heating the mixture to a DONALD G..ROGERS.

temperature of about 150155 0., and main- HAROLD T. STOWELL. 

